This invention relates to a liquid coater for supplying a liquid coating material to a printing press cylinder for transfer to the paper web or sheet being printed. The mechanism has particular application to a printing press having a recessed cylinder. The mechanism permits the coating rollers and tray holding the coating material to be selectively moved into and out of position for coating. When the coating rollers and tray are moved out of position they will not interfere with the printing operation or otherwise be in the way of the press operator.
It has become common practice to utilize a coater for applying a liquid coating material to the blanket of a web offset printing press so that the printed sheet or web which is moving through the press can be coated. The coating material is usually an aquaeous coating which when dry renders the printed paper resistent to moisture and oils and prevents smearing. The coaters for applying this material generally utilize a tray for holding the liquid coating material and a feed roller rotating in the liquid coating material in the tray. A coater roller is in rotating engagement with the feed roller and also in rotating engagement with the blanket cylinder of the printing press. The coating material is picked up from the tray by the feed roller, transferred to the coater roller, and retransferred to the blanket by the coater roller.
Since the coater is an adjunct to the printing press, the main function of the press being to print, the coater must be capable of being moved into and out of position with respect to the blanket cylinder. The coater may be rotrofitted onto existing presses, or it may be worked into existing press designs. In most presses, the coater can be easily added and is not in the way of the printing operation of the press. However, in a number of printing presses, the blanket cylinder is recessed so that there is very little room for the coater to be moved into position for coating the blanket cylinder. Heretofore, it has not been possible to utilize a coater with such presses because the coater would be in the way of the press operator and interfere with the normal printing operation of the press. Thus, with presses such as the "Heidelberg Speed Master", a separate coater was heretofore required.
The present invention obviates the need for a separate coater and permits the coater to be mounted on presses which have a recessed blanket cylinder. In accordance with this invention, the coater may be moved into and out of position so that it does not interfere with the printing operation of the press and it permits the printed material to be coated as it is being moved through the printing press, thus, not only saving equipment, but saving time and labor by eliminating a separate operation on a separate piece of equipment.
In accordance with one aspect of the invention, the coater mechanism for applying a liquid coating material to the recessed printing press cylinder comprises a frame, a tray mounted on the frame for holding a supply of the coating material and roller means carried by the frame for transferring the coating material from the tray to the printing press cylinder. Track means is attached to the printing press and extends from adjacent the printing press cylinder to a point remote from the printing press cylinder. The tray and roller means are preferably mounted on a subframe attached and carried by the coater frame and the coater frame in turn in mounted on the track means. Means is provided for moving the frame and the subframe with the tray and roller means carried thereon, along the track means into and out of position adjacent the printing press cylinder, and means is provided for moving the roller means into and out of position for engagement with the printing press cylinder after the coater frame has been moved to its position adjacent the cylinder. It is preferred that there be a means for locking the coater frame in its position adjacent the cylinder when it has been moved into that position. Once the frame has been moved into its position adjacent the printing press cylinder, and the subframe has been moved to position the roller means into contact engagement with the printing press cylinder, the liquid coating material may be picked up from the tray by the roller means and applied to the printing press cylinder.
In the preferred embodiment, the track means comprises a pair of rectilinear tracks which extend upwardly and rearwardly and roller means on the frame rollably engage the track means so that the frame may be moved relative to the track means toward and away from the printing press cylinder.
The frame may be moved along the track means by means of a pair of internally threaded nut members mounted for rotation adjacent opposite sides of the coater frame. Extending through the nut members and mounted in fixed position relative to the track means are a pair of spaced parallel, externally threaded rods. The drive means includes means interconnecting the nut members and for rotating them in unison selectively in a direction which will move the frame toward the press cylinder and in the opposite direction away from the press cylinder.
The subframe is preferrably pivotally mounted on the front arms of the frame so that when the frame has been moved to its lower-most position adjacent the press cylinder, the subframe may be pivoted or tilted forwardly to bring the roller means into contact with the printing press cylinder so that the coating material may be applied to the printing press cylinder.